Although I am not an old guy, I will throw my two cents in. If the coach just mentions it, I might not say anything in return. He may just want you to be aware of the foul count to try and gain an "edge" as some officials may get worried about it and call something that they might normally pass on. Doesn't work on me but....
If the coach is actually making an issue of it and approaches the situation with some degree of professionlaism, I might respond you are right coach but you are pressing and playing man to man and they are playing a zone and you are shooting jumpers (for example).
Lastly if the coach is being a jacka$$ about it and implying that we are not being fair, I will tell him that the count "is what it is and we are calling the game as we see it." End of conversation, if he persists with it he may end up with a T because the implication is the we are cheating. I won't have that.
The key to handling a lopsided foul count is to make sure that you don't miss one on the team that has the lower count. I am not advocating looking for something to call or making something up, however if there is an actual foul that creates an advantage for the other team and you miss it or pass on it the coach will give it to you and you don't have any ground to stand on to defend yourself
For what its worth....